This application is based on and claims priority from JP 2001-344448 filed on Nov. 9, 2001, JP 2002-217448 filed on Jul. 26, 2002 and JP 2002-284779 filed on Sep. 30, 2002, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a structure for standardizing at least one kind of part of an endless track so that parts can be used for the same size of construction vehicles having different structural specifications of a plurality of construction vehicle makers.
2. Description of Related Art
As disclosed in Japanese Patent Publication HEI 8-318879, an endless track includes at least one kind of part including at least one of (a) a link belt including a pair of links, and a pin and a bushing for coupling adjacent pairs of links, and (b) a shoe coupled to each pair of links of the link belt.
The structural specification for an endless track issued from a construction vehicle maker to an endless track maker is different among construction vehicles manufactured by different construction vehicle makers, even if the size of the construction vehicles is the same among five sizes of construction vehicles, including a super-large size, a large size, a middle size, a small size, and a super-small size.
More particularly, a diameter and a length of the pin, an outside diameter, an inside diameter and a length of the bushing, a diameter of a pin hole, a diameter of a bushing hole, a diameter of shoe bolt holes and a pitch of the shoe bolt holes, of the link, an inside span and an outside span of the pair of links, a configuration of the shoe, and a diameter of each of four coupling holes and a pitch of the coupling holes of the shoe, respectively, are varied between the construction vehicles of different construction vehicle makers, even if the construction vehicles are of the same size.
When the size of the construction vehicle changes, a configuration and a dimension of each kind of part of the endless track also change according to the change in size of the construction vehicle.
When the endless track maker manufactures endless tracks for the same size of construction vehicles of different construction vehicle makers, the endless track maker has to manufacture links, pins, bushings and shoes that can be used only for the corresponding construction vehicles of each construction vehicle maker. Since the configuration and dimension of the parts for the endless track change according to a change in size of the construction vehicle, for each part (the pin, the bushing, the paired links, and the shoe) of the endless track, the endless track maker has to manufacture a large number (the number of the construction vehicle makersxc3x97the number (five) of the sizes of the construction vehicles) of kinds of parts. As a result, the number of the kinds of the parts is very large, and a reduction in cost due to mass production has been difficult.
An object of the present invention is to provide a structure for standardizing at least one kind of part of an endless track so that parts having the same structure can be commonly used for the same size of construction vehicles having different structural specifications of a plurality of construction vehicle makers.
According to the present invention, the above object can be performed by a structure for standardizing at least one kind of part of an endless track so that parts can be used for the same size of construction vehicles having different structural specifications of a plurality of construction vehicle makers. The at least one kind of part includes at least one of (a) a link belt including a pair of links, and a pin and a bushing for coupling adjacent pairs of links, and (b) a shoe coupled to each pair of links of the link belt.
In the structure, except for a length of the pin, a length of the bushing, at least one of an inside span and an outside span between the pair of links, and a diameter and a position of shoe bolt holes formed in the pair of links, the following structural unification is performed.
(a) When the at least one kind of part is a link belt, each of a configuration and a dimension, in an extending direction of the endless track and two directions perpendicular to the extending direction of the endless track, of each link of the pair of links, the pin and the bushing is unified over the same size of construction vehicles having different structural specifications of the plurality of construction vehicle makers.
(b) When the at least one kind of part is a shoe including four coupling holes for coupling the shoe to the pair of links of said link belt, each of a position, a configuration and a size of the four coupling holes is unified over the same size of construction vehicles having different structural specifications of the plurality of construction vehicle makers.
According to the above standardizing structure, parts having the same structure can be commonly used for the same size (the same size among a super-large size, a large size, a middle size, a small size, and a super-small size) of construction vehicles having different structural specifications of the plurality of construction vehicle makers.
As a result, the material cost for the parts and the forging cost of the link can be reduced. Further, the exchange of jigs for machining the link and the coupling holes of the shoe is unnecessary, and productivity is increased.